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Draft inducer out of balance - causing vibration

Paul Wolf
Paul Wolf Member Posts: 35
Greetings, I have a newly installed Purepro ADV sealed combustion boiler. This is very similar to a Burnham ESC model as they are both made by US Boiler. It been working absolutely flawlessly since installation.

Since installation this boiler has had a low frequency vibration. I have positively isolated it to the draft inducer.  It appears to be out of balance.  I have taken a few steps to mitigate the vibrations. 

1. I've insulated (isolated) the PVC intake and Z-Flex stainless exhaust pipe hangers with automotive exhaust hangers. They are installed between the hangers and the ceiling (flooring) joists.  This has reduced the vibration by about 60 percent.

2. I've wrapped 5 lbs of lead flashing around the stainless Z-Flex exhaust and this has dampened the vibrations some more, but it is still bothersome.  The vibration "telegraphs" through the framing of the house to the living areas.  

There was a "sheet metal" type rattle that coincided with the out of balance draft inducer, but I was able to bend the sheet metal a bit to get rid of the rattle.

So...Where am I going?  This is a brand new boiler. Do all draft inducers of this type vibrate like this?  If not, is there a means of balancing it somehow?  Or is the solution to replace it?  Will the replacement be just as bad, or worse? Or is this simply a case of "they all do that"?  



    JUGHNE Member Posts: 10,278
    Is the vibration there for the "pre purge" and "post purge" fan running OR just when the boiler fires between those points in time?
  • Paul Wolf
    Paul Wolf Member Posts: 35
    JUGHNE. Thanks for the reply. Yes, pre and post purge. Anytime the draft inducer is turning, the vibration is present.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,916
    No, To your question @Paul Wolf
    If the draft fan is out of balance then it is a warranty issue and you should be given a new one at no charge from the manufacturer. If there is an installer pro involved, check your contract agreement with the installer, they may also cover warranty labor.

    The manufacturer does not cover labor.
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,916
    Have you actually looked at the fan itself? Is there any debris from installation stuck on the fan?
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • Paul Wolf
    Paul Wolf Member Posts: 35
    Ed, Thanks. I have not had the fan out yet. It does sound very much like my car's heater blower when there is something in the squirrel cage. It doesn't look like too tough of a job. Four screws and a connector. If that's all it takes I may have a go. I was more concerned that it may need balancing. I have no idea how to do that.

    The installer is aware of my issue. We've discussed it a few times. He lost a few techs temporarily to covid and been busy. The last time we spoke he said he was going to try and get the Purepro rep out for a look-see. I haven't heard back yet, nor (in his defense) have I tried to contact him since. He's a nice guy and he and his crew are very easy to work with. I don't want to be a pest if it's a "they all do that" type of thing. My point in posting was to see if the general consensus was that they in fact "all do that".

    Just how quiet should this blower be?
    EBEBRATT-Ed Member Posts: 13,100
    @Paul Wolfe

    Noise from a blower is one thing. Vibration is another. I would get it fixed sooner than later while it is under warranty.

    Before you pull it out to check for debris check the parts diagram, you may need a gasket or something
  • Paul Wolf
    Paul Wolf Member Posts: 35
    Thanks Ed, I can see the gasket pretty well, and the boiler being only 3 months old, (from what I can see) it's intact. I don't know that I can check for debris without removing it.

    Now that I know it's not "normal", I'm going to give him another call this week and see what his plan is. I don't know how the "trade" warranty process works for something like this. Does the manufacturer usually take the installers word and forward a part, or do they have to have a rep come out and verify the issue?

    I was in the computer repair business for many years. In every case the manufacturer would forward a new part based on my word and I would send the defective one back.

    It's quieter than my old Burnham oil boiler was, and louder than my old Buderus GB 142 that this replaced. It's not the end of the world, just annoying every time the boiler comes on. Thanks for all your advice and help.